DE102008051546B4 - Air spring system for a motor vehicle with at least one valve arrangement for a lift axle of the motor vehicle - Google Patents

Abstract

Air spring system for a motor vehicle, having at least one valve arrangement for a lift axle (28) of the motor vehicle, having at least one valve (36) for an air spring (22) for damping the lift axle (28), with at least one valve (34) for an air spring ( 20) for raising and lowering the lift axle (28), the at least two valves (34, 36) being combined to form a valve unit (38) and having at least one further axle (30, 32), which respective air springs (24, 26) for lifting and lowering the axis (30, 32) are assigned, wherein the air springs (24, 26) via these associated, electrically switchable valves (16, 56) are acted upon with compressed air, characterized in that a lifting and lowering device (72 ) is provided for manual, mechanical lifting and lowering of the vehicle, wherein the valves (16, 56) of the at least one axis (30, 32) are switchable by pressurization, wherein the lifting and lowering device (72) respective control lines (94, 96 ) Trains are arranged, which are connected for switching by applying to the pressure medium with the corresponding valves (16, 56).

Description

The present invention relates to an air suspension system for a motor vehicle with at least one valve arrangement for a lift axle of the motor vehicle according to the preamble of patent claim 1.

The DE 36 38 849 A1 discloses an air suspension for a double axle vehicle. The DE 195 46 324 C2 shows a control block for an air suspension system. The DE 36 28 681 A1 also an air suspension for a vehicle with double axle. The DE 34 28 867 A1 describes an air spring device for vehicles. The DE 20 56 634 A discloses an air suspension, especially for motor vehicles.

Lift trucks are known in trucks, trailers or semitrailers, which are provided in particular in the rear of the truck or in the front of a trailer (trailer axle). The lift axle is intended to receive a part of the total weight of the vehicle when the vehicle is loaded, for example a loaded truck. In particular, when the vehicle is unloaded, the lift axle can be raised, so that the associated wheels have no contact with the road. As a result, in particular fuel should be saved and abrasion of the tires should be avoided. An air spring device with a valve device for such a truck is already out of the DE 103 54 056 A1 to be known as known.

Object of the present invention is therefore to provide a valve assembly or a spring system for a vehicle, in particular a truck to create, which are simple in construction and ensure trouble-free operation of the vehicle.

This object is achieved by an air suspension system for a motor vehicle with at least one valve assembly for a lift axle of a vehicle having the features of claim 1. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the respective dependent claims.

The air spring system for a motor vehicle with at least one valve arrangement for a lift axle of a vehicle, in particular a motor vehicle, according to claim 1 comprises at least one valve for at least one air spring to spring the lift axle and at least one valve for at least one air spring for lifting and lowering the lift axle. Respective air springs for springing an axle are also referred to below as spring elements. Furthermore, the at least two valves are combined to form a valve unit. Thus, it is possible to combine the two valves into a compact and interference-resistant unit in a block or a housing, so that this or this can be easily mounted on the vehicle. In particular, it is conceivable that the valve unit is arranged, for example, on the at least one spring element for raising and lowering the lift axle or on the spring element for springing the lift axle. It may also be that a valve unit is used in particular for controlling two spring elements for springs of the lift axle. However, it may also be that a respective valve unit is provided for each spring element for springing the lift axle, in particular when two spring elements are also used for lifting and lowering the lift axle.

In addition, the air suspension system comprises at least one further axis, which respective air springs are assigned to raise and lower the axis, wherein the air springs are acted upon by these compressed, electrically switchable valves. Respective air springs. According to the invention, it is provided that a lifting and lowering device for manual, mechanical lifting and lowering of the vehicle is provided, wherein the valves of the at least one axis are switchable by pressurization, wherein the lifting and lowering device are associated with respective control lines, which for switching are connected by applying to the pressure medium with corresponding valves.

The valve unit is characterized in a further embodiment of the invention in that it has corresponding line inputs for lines of a pressure medium. In other words, the valve unit is preferably designed so that it forms a finished assembly with the valves to which only the corresponding lines of the pressure medium must be connected to the vehicle. This applies in just as much manner in a further embodiment of the invention for at least one line input for a control line, in particular for connection to a central control device. Again, preferably only a plug connection or the like. Provided for the control line.

In an advantageous embodiment of the invention, the at least one valve for the air spring for lifting and lowering the lift axle in the raised or lowered end position of the lift axle is closed. This has the particular advantage that, for example, when driving the vehicle no permanent, such as electrical control signal needs to rest, but rather that occur due to the closed position of the valve in the raised or lowered end position of the lift axle no change in the state of the driven by the valve spring element can. Even with a failure of the valve assembly, such as a failure of the power supply, the lift axle thus remains in their respective raised or lowered position.

A possible change in the state of the spring element actuated by the valve can also be detected, if appropriate, by a pressure sensor or the like which is arranged, for example, in the spring element for raising and lowering the lift axle.

In a further embodiment of the invention, it has proven to be advantageous if the at least one valve is switched de-energized in the raised or lowered end position of the lift axle. This has the particular advantage that the energy consumption of the valve assembly and thus the fuel consumption of the vehicle can be reduced.

It is also advantageous if the valve unit comprises a type identification. This makes it easy to identify the valve unit - for example, for replacement.

Another advantage is that the valve arrangement, in particular the valve unit, has a decentralized control device. This has the particular advantage that few control lines of a central control device of the spring system are required, but rather that the valve assembly at least partially works independently and, for example, a signal of a height measuring device of the spring element can process directly to control the valve.

The air spring system according to claim 12 comprises at least two spring arrangements, which are assigned to a respective axis of the vehicle and which each have at least one spring element, wherein a first spring element of the first axis is associated with a height sensor device for determining a spring height of the spring element or the corresponding first axis, wherein, according to the invention, the height sensor device of the first spring element of the first axis additionally has a sensor device, in particular with a pressure sensor, which communicates with a sensor device, in particular with a pressure sensor, of the second spring element of the second axis, wherein the second axis with the first axis by means of the height sensor device is mitsteuerbar. Thus, only one height sensor device is required for at least two axes. The coordination of the axes with one another can then be carried out by cost-effective sensor devices, for example with pressure sensors, wherein, for example, a pressure within the one spring element of one axis, in the region of which the height sensor device is provided, is measured and, as a result, the pressure within the other spring element the second axis is adjusted by means of the corresponding pressure sensor.

• 1 eine nicht mehr vom Gegenstand des Patentanspruchs 1 umfasste Darstellung eines Schaltplans einer Federanlage, insbesondere einer Luftfederanlage, für ein Fahrzeug, insbesondere einen Lastkraftwagen, wobei eine Ventilanordnung mit wenigstens einem Ventil für eine Luftfeder zum Federn der Liftachse und mit wenigstens einem Ventil für ein Federelement zum Heben und Senken der Liftachse vorgesehen ist, welche zu einer Ventileinheit zusammengefasst sind, und wobei zwei Federanordnungen vorgesehen sind, welche einer jeweiligen Achse des Fahrzeugs zugeordnet sind und welche jeweils wenigstens eine Luftfeder aufweisen, wobei einem ersten Federelement der ersten Achse eine Höhensensoreinrichtung zur Ermittlung einer Federhöhe der Luftfeder bzw. der korrespondierenden ersten Achse zugeordnet ist, welche zusätzlich eine Sensoreinrichtung, insbesondere mit einem Drucksensor aufweist, die mit einer Sensoreinrichtung, insbesondere mit einem Drucksensor, der zweiten Luftfeder der zweiten Achse kommuniziert, wobei mittels der Höhensensoreinrichtung die zweite Achse mit der ersten Achse mitsteuerbar ist;
• 2 eine nicht mehr vom Gegenstand des Patentanspruchs 1 umfasste ausschnittsweise Darstellung einer Alternative des Schaltplans der Federanlage gemäß 1;
• 3 eine Darstellung eines Schaltplans einer Federanlage, insbesondere einer Luftfederanlage, für ein Fahrzeug, insbesondere einen Lastkraftwagen, nach einer zur Ausführungsform gemäß 1 alternativen Variante, wobei insbesondere eine Hebe- und Senkeinrichtung zum manuellen Heben und Senken des Fahrzeugs vorgesehen ist;
• 4 eine ausschnittsweise Darstellung einer Alternative des Schaltplans der Federanlage gemäß 3;
• 5 eine nicht mehr vom Gegenstand des Patentanspruchs 1 umfasste Darstellung eines Schaltplans einer Federanlage, insbesondere einer Luftfederanlage, für ein Fahrzeug, insbesondere einen Lastkraftwagen, nach einer zu den Ausführungsformen gemäß 1 und 3 alternativen Variante, wobei insbesondere eine alternative Entlüftung der als Luftfedern ausgebildeten Federelemente einer Liftachse dargestellt ist;
• 6a-g jeweilige, nicht mehr vom Gegenstand des Patentanspruchs 1 umfasste ausschnittsweise Darstellungen von Schaltplänen von alternativen Ventilanordnungen für ein jeweiliges Federelement, welche zu einer Ventileinheit zusammengefasst sind,
• 7 eine weitere, nicht mehr vom Gegenstand des Patentanspruchs 1 umfasste Darstellung eines Schaltplans einer Federanlage nach einer alternativen Variante.

Further details of the invention will become apparent from the following description of preferred embodiments and from the drawings; these show in:

• 1 a representation of a circuit diagram of a spring system, in particular an air spring system, for a vehicle, in particular a truck, no longer encompassed by the subject-matter of patent claim 1, wherein a valve arrangement with at least one valve for an air spring for springs of the lift axle and with at least one valve for a spring element for Lifting and lowering of the lift axle is provided, which are combined to form a valve unit, and wherein two spring arrangements are provided, which are associated with a respective axis of the vehicle and which each have at least one air spring, wherein a first spring element of the first axis, a height sensor means for determining a Spring height of the air spring or the corresponding first axis is associated, which additionally comprises a sensor device, in particular with a pressure sensor having a sensor device, in particular with a pressure sensor, the second air spring of the second axis communicates, wherein by means of the height sensor means, the second axis is mitsteuerbar with the first axis;
• 2 a sectional representation of an alternative of the circuit diagram of the spring system according to no longer included in the subject matter of patent claim 1 1 ;
• 3 a representation of a circuit diagram of a spring system, in particular an air spring system, for a vehicle, in particular a truck, according to one of the embodiment according to 1 alternative variant, wherein in particular a lifting and lowering device for manually raising and lowering of the vehicle is provided;
• 4 a detail of an alternative of the circuit diagram of the spring system according to 3 ;
• 5 a representation of a circuit diagram of a spring system, in particular an air spring system, for a vehicle, in particular a truck, according to one of the embodiments according to no longer included in the subject matter of patent claim 1 1 and 3 alternative variant, in particular an alternative venting as Air springs formed spring elements of a lift axle is shown;
• 6a-g respective sectional representations, no longer encompassed by the subject-matter of claim 1, of circuit diagrams of alternative valve arrangements for a respective spring element, which are combined to form a valve unit,
• 7 a further, no longer covered by the subject matter of claim 1 representation of a circuit diagram of a spring system according to an alternative variant.

In 1 a circuit diagram of an air spring system for a truck is shown. From a pressure generator is in 1 an accumulator 10 recognizable, which of a compressor not shown via a line 12 in which a check valve 14 is integrated, is fed. Furthermore, the pressure generating device is a valve 16 assigned, which is presently designed as a magnetically switchable 3/2-way valve.

About one after the valve 16 arranged line 18 are several spring elements 20 . 22 . 24 . 26 of axes explained in more detail below 28 , 30, 32 can be supplied. In particular, the lift axle is recognizable 28 which the spring elements 22 a corresponding spring arrangement 23 for springs of the lift axle 28 during driving, etc. includes. Respective spring elements 22 . 24 . 26 For springs of respective axes can also be used as air springs 22 . 24 . 26 be designated.

In addition, this is at least one spring element 20 provided, which for lifting and lowering the lift axle 28 is provided. Instead of a spring element 20 would also be several, in particular two spring elements 20 , conceivable.

Furthermore, it can be seen that the spring element 20 for lifting and lowering the lift axle 28 and the corresponding spring element 22 for springs of the lift axle 28 in driving, etc. each one valve 34 respectively. 36 , which are designed as magnetically switchable 2/2-way valves, are assigned. Both valves 34 . 36 are closed in the unswitched initial position shown here.

Furthermore, it can be seen that the two valves 34 . 36 form a valve arrangement which leads to a valve unit indicated by a dashed line 38 are summarized. This valve unit 38 For example, it may have a block or a housing, wherein another feature is that the valve unit 38 corresponding line inputs and outputs 40, 42 for lines of the pressure medium - here compressed air - has. It can be seen, for example, that via the line inlet and outlet 40 both the valve 34 as well as the valve 36 be acted upon with compressed air.

It can for both spring elements 22 one valve unit each 38 be provided, namely in particular then, although two spring elements 20 with associated valves 34 for lifting and lowering the lift axle 28 be used. In addition, where appropriate, two or more spring elements 20 respectively. 22 through one and the same valve unit 38 to be controlled. In the present case, both spring elements 22 for springs of the lift axle 28 while driving etc. by one and the same valve 36 driven.

In addition to the line inputs and outputs 40, 42 includes the valve unit 38 at least one line input and output 44 for a control line 46 for connection to a central control device 48 ,

Finally, in the present case, two pressure sensors 50 . 52 provided by means of which the pressure in the respective spring element 20 respectively. 22 can be measured.

Also the pressure sensors 50 . 52 are in the valve unit 38 integrated. The pressure sensors 50 . 52 can thereby the air pressure within the bellows of the spring element 20 respectively. 22 measure by these are connected via a corresponding line or a channel with the corresponding bellows. It remains to be noted, however, that the pressure sensors 50 . 52 even within the block or housing of the valve unit 38 arranged and only via a respective channel with the interior of the spring element 20 respectively. 22 pressure-connected.

It is now apparent that the lift axle 28 Can be lifted by the valve 34 and the valve 16 to be switched, which causes compressed air in the line 18 is applied, which by switching the valve 34 gets into the bellows of the spring element 20. A lowering takes place by the valve 16 remains unswitched while the valve 34 is switched so that the compressed air via a the valve 16 then arranged silencer 54 reaches the outside. For lifting the lift axle 28 Thus, the or the spring elements are preferred 22 first by switching the valve 36 vented before following the two valves 16 and 34 be switched, whereby according to compressed air in the spring element 20 arrives. When lowering the lift axle 28 is preferably first the spring element 20 vented by the valve 34 is switched and thus the air over the unswitched valve 16 and the muffler 54 can escape. Following this, then can within the respective spring elements 22 to build up a pressure by the valves 16 and 36 be switched. Following this, the spring elements 22 the spring arrangement 23 again for driving - so to the springs of the lift axle 28 - be used. Of course, it would also be conceivable, the total escaping air back into the compressed air reservoir 10 to lead back. It is therefore apparent that in the present case for lifting and lowering the lift axle 23 or of the spring element 20 either the valve 16 switched or not switched while the valve 34 the valve unit 38 is switched in both cases.

The non-pressurized remaining of the valve 34 For example, when driving has the significant advantage that no currents flow while driving and basically no change in the state of the air spring or the spring element 20 can occur. A possible change is made by the pressure sensor 50 monitored, so that at any time can be admitted according to air or even dismissed.

For lifting the lift axle 23 can it - as explained above - also be necessary that the or the spring elements 22 also be vented. This is also done via the valve 16 , which remains in its rest position and is therefore unswitched. For driving, so if the or the spring elements 22 To be ventilated, is the valve 16 at least temporarily switched, so that in the line 18 Air with a corresponding pressure is applied, which for the unfolding of the spring bellows of the respective spring element 22 can be used.

The axes 30 and 32 In the present case, they are close to the lift axle 28 arranged drive axle 30 as well as the front axle 32 of the truck. Each spring element 24 respectively. 26 is in each case designed as a 2/2-way valve designed valve 56, 58, which in turn are de-energized or closed in the initial state. By switching the respective valve 56 . 58 is the corresponding spring element 24 respectively. 26 filled with compressed air, provided the valve 16 is also switched. For bleeding the spring elements 24 respectively. 26 becomes the respective valve 56 . 58 switched again, but not the valve 16 , About the line 18 Thus, the compressed air can escape or alternatively flow back to the compressed air reservoir 10.

It can be seen that in the present case each spring element 24 respectively. 26 a valve 56 . 58 assigned. If necessary, it would also be conceivable to use the spring elements 24 or 26 of the respective spring arrangement 64 . 66 the assigned axis 30 . 32 only one valve at a time 56 . 58 assigned. Furthermore, it can be seen that the respective valve 56, 58 with a corresponding sensor device in the form of a pressure sensor 60 and a respective height sensor 62 a height sensor device 64 again a respective valve unit 38 forms, which in the manner of the previously described valve unit 38 is designed. By means of the height sensor device 63 is the currently set height of the spring element 24 . 26 detectable, using the pressure sensor 60 a pressure within the bellows of the spring element 24 respectively. 26 is detected. It should be noted that for both spring elements 24 respectively. 26 the respective spring arrangement of the corresponding axis 30 . 32 in principle also a valve unit 38 enough.

As in 1 is recognizable, are for the axles 23 and 64 two spring assemblies 23 and 64 are provided, which each have at least one spring element 22 . 24 have, wherein the spring element 64 the first axis (drive axle 30 ) the height sensor device 63 for determining the spring height of the spring element 24 or the corresponding first axis 64 is assigned, which in addition the sensor device with a pressure sensor 60 having, with the sensor device with the pressure sensor 52 of the spring element 22 the second axis 23 (Lifting axle 28 ), whereby by means of the height sensor device 63 the second axis 28 with the first axis 30 is mitsteuerbar. In other words, for both valve units 38 the two spring elements 22 respectively. 24 only a height sensor device 63 on the drive axle 64 needed. The adjustment of the height of the lift axle 28 via the two pressure sensors 60 . 52 which can be matched in their pressure, for example, so that both spring elements 22 respectively. 24 have the same height. On a separate height sensor for the lift axle 28 can thus be dispensed with.

Finally, in 1 respective control lines 46 recognizable, over which the central control device 48 with the respective valve units 38 connected is.

2 shows a partial view of an alternative spring system according to 1 , wherein a valve unit 38 is provided, by means of which both spring elements 26 - For example, the front axle 30 - are controllable. In this case, the valve unit comprises 38 two valves 68 . 70 and a throttle 71 , In addition, in turn, a height sensor device 63 and a pressure sensor 60 intended. In principle, just the front axle is suitable 30 especially good for using only one valve unit 38 because the front axle 30 usually a rigid axle. The valve unit 38 is in turn related to the type of 1 described valve unit 38 educated. That means the valves 68 , 70 and the throttle 71 and the height sensor device 63 are integrated in a common block or in a common housing. This block again shows corresponding line inputs and outputs for lines of the pressure medium and at least one line input or output for a control line 46 on. Through the two valves 68 respectively. 70 is the respective spring element 26 ventilated or vented, in each case via the line 18 as well as the valve 16 , About the throttle 71 are the two spring elements 26 interconnected to a throttled pressure equalization between the two spring elements 28 to reach, so that they essentially always have the same spring height. For this reason, it is sufficient if only one of the spring elements 26 a height sensor device 63 assigned. This height sensor device 63 again, is essentially also in the valve unit 38 integrated.

3 shows a representation of the circuit diagram of the spring system according to one of the embodiment according to 1 alternative variant, where initially the axes 28 , 30 and 32 as lift axle 28 as well as trailer axles 30 . 32 a trailer are formed.

Another modification concerns a type identifier 90 in the form of an RFID, in which by electronic means an assignment of the respective valve unit 38 can be achieved. The type indicator 90 is particularly advantageous because both the valves 34 and 36 as well as the pressure sensors 50 and 52 into the valve unit 38 are integrated. The type indicator 90 therefore helps that the respective valve unit 38 or their equipment can be easily identified. This of course applies to all valve sensor units 38 of the type described here. In addition, two spring elements are present 20 provided for lifting and lowering the lift axle 28.

Another modification concerns the fact that the two trailer axles 30 . 32 only via a valve sensor unit 38 with the valve 56 to be controlled.

Finally, there is a modification in that by mechanical means lifting and lowering these four air springs 24 . 26 or the two trailer axles 30 . 32 is possible, for example, to facilitate loading.

This is done by means of a lifting and lowering device 72 for manually raising and lowering the vehicle or axles 30 . 32 , The lifting and lowering device 72 includes two valves 74 . 76 and a double check valve 78 , First, it should be noted that the two valves 74 . 76 be switched by manual operation between the two positions. The one, shown on the left valve 74 serves to lift, the other valve 76 to sink. Output side of the two valves 74 , 76 is the double check valve 78 provided to which the control lines 94 and 96 connect. Depending on which valve 74 respectively. 76 is actuated, thus becomes the control line 94 or 96 pressurized with air pressure. Based on this pressurization of the control lines 94 . 96 are the two, in themselves magnetically switchable valves 56 . 16 by means of through the valves 74 . 76 initiated compressed air switchable. This principle is below in conjunction with 4 explained.

4 shows a partial view of an alternative of the circuit diagram of the spring system according to 3 , While in 3 for example, a valve 56 is used, which is both magnetically and pneumatically switchable shows 4 an arrangement 56 as an alternative to the valve 56 according to 3 , In this case, a pilot valve 80 and a holding valve 98 intended. The pilot valve 80 is magnetically switchable while the holding valve 98 by compressed air, which through the pilot valve 80 can pass through, is switchable. While the pilot valve 80 a 3/2-way valve is the holding valve 98 a 2/2-way valve. The pilot valve 80 is via a double check valve 100 over the line 18 with the valve 16 connected. The double check valve 100 is a pressure reducer 102 downstream. It can now be seen that when switching the left valve 74 through which a lifting of the axle 30 ( 3 ) is caused, both a pressure in the control line 94 as well as the control line 96 is applied. The pressure within the control line 94 causes a flow through the pilot valve 80 so that the holding valve 98 is switched. The pressurization of the control line 96 causes the valve 16 is switched. Overall, it is thus achieved that both the valve 16 as well as the valve 98 are switched, whereby the spring element 24 pressurized air is.

In the opposite case, if a lowering is to take place and consequently the valve 76 is pressed, only the control line 94 pressurized. Through the double check valve 78 on the other hand, a pressurization of the control line 96 prevented. Consequently, via the control line 94 turn the holding valve 98 switched while the valve 16 remains unmoved. This causes via the switched holding valve 98 and the unswitched valve 16 Air from the spring element 24 can escape, causing the axis 30 is lowered.

5 shows an illustration of a circuit diagram of the spring system according to one of the embodiments according to 1 and 3 alternative variant, and in particular another variant of the venting of the spring element 22 is shown. As already related to 1 has been explained, it is in principle desirable that the or the spring elements 22 the lift axle 28 then be vented when the spring element 20 for lifting the lift axle 28 is ventilated. In 5 is therefore an alternative to 1 recognizable. Will be the valve 34 for venting the spring element 20 switched, then becomes a control line 104 pressurized with compressed air. Via a control line 104 becomes a basically magnetically switchable valve 82 which is the valve 36 according to 1 corresponds, pressurized with compressed air and therefore closed. The inside of the spring element 20 Compressed air can thus via a bypass 106 under flow through a check valve 84 and another line 108 back to a valve 86 reach. This valve 86 must be switched separately, so that a venting of the spring element 22 can be done. Thus, it can be seen overall that when pressure is applied to the spring element 20 automatically a venting of the spring element 22 takes place, so that, for example, the lift axle 28 by means of the spring element 20 raised and at the same time their spring elements 20 be vented to the suspension in the pre-operation. For aerating the spring elements 22 as well as the spring elements 24 serves the respective valve 110 , If this is switched, compressed air reaches both the spring elements 22 as well as in the spring elements 24 , The valve 34 can be switched, so that the spring element 20 is vented. The valve must be the same 86 be switched.

In the 6a-g are respective partial representations of circuit diagrams of alternative valve assemblies or valve units 38 for a respective spring element 24 . 26 shown.

6a shows a valve unit 38 in which besides the air spring 24 and the valve 56, a transponder or the like. Identification 90 is provided, which allows an assignment.

6b shows a height sensor 62 in the air spring 24 is integrated.

In 6c is also a pressure sensor 60 also integrated.

6d shows a basic variant.

6e additionally shows a decentralized control 92 ,

6f shows a valve unit 38 especially for the lift axle 28 ,

6g corresponds to the embodiment according to 3 , 5 and provides a supplement for example from 1 It is stated that the pressure in the air spring 24 for lifting and lowering is then maximum, if it is minimal in the lift axle or vice versa.

Finally shows 7 a further, partial representation of a circuit diagram of a spring system according to an alternative variant. 7 shows in particular an alternative of the valve unit 38 for controlling the spring element 20 or the spring elements 22 for lifting and lowering the lift axle 28 or for suspension during driving. In particular, the two pressure sensors are shown 50 . 52 , by means of which a respective pressure within the spring element 20 or the spring elements 50 is measurable. While lowering or lifting the lift axle 28 takes place between a respective minimum value and a maximum value, a constant comparison of the pressure values within the spring element 20 respectively. 22 by means of the pressure sensors 50 respectively. 52 , In this case, an approximately equal pressure between the spring elements is always in the present case 22 or the spring element 20 set. This can be done, for example, by alternately switching the valves 34 and 36 respectively. So there is always a venting of the respective one spring element 20 or 22 and vice versa venting of the other spring element 22 and 20 instead.

Claims (12)

Air spring system for a motor vehicle, having at least one valve arrangement for a lift axle (28) of the motor vehicle, having at least one valve (36) for an air spring (22) for damping the lift axle (28), with at least one valve (34) for an air spring ( 20) for raising and lowering the lift axle (28), the at least two valves (34, 36) being combined to form a valve unit (38) and having at least one further axle (30, 32), which respective air springs (24, 26) for lifting and lowering the axis (30, 32) are assigned, wherein the air springs (24, 26) via these associated, electrically switchable valves (16, 56) are acted upon with compressed air, characterized in that a lifting and lowering device (72 ) is provided for manual, mechanical lifting and lowering of the vehicle, wherein the valves (16, 56) of the at least one axis (30, 32) are switchable by pressurization, wherein the lifting and lowering device (72) respective control lines (94, 96 ) train are arranged, which are connected for switching by applying to the pressure medium with the corresponding valves (16, 56). Air spring system after Claim 1 , characterized in that the valve unit (38) has corresponding line inputs (40, 42) for lines of a pressure medium. Air spring system after Claim 1 or 2 , characterized in that the valve unit (38) has at least one line input (44) for a control line for connection to a central control device (48). Air suspension system according to one of Claims 1 to 3 , characterized in that at least one pressure sensor (50, 52, 60), in the valve unit (38) is integrated. Air suspension system according to one of Claims 1 to 4 , characterized in that the valve unit (38) comprises a type designation (90). Air suspension system according to one of Claims 1 to 5 , characterized in that the valve unit (38) has a decentralized control device. Air suspension system according to one of Claims 1 to 6 , characterized in that the at least one valve (34) for the air spring (20) for raising and lowering the lift axle (28) in the raised or lowered end position of the lift axle (28) is closed. Air spring system after Claim 7 characterized in that the at least one valve (34) for the air spring (20) for raising and lowering the lift axle (28) is de-energized in the raised or lowered end position of the lift axle (28). Air suspension system according to one of Claims 1 to 8th , characterized in that the at least two air springs (22, 24, 26) of different axes (30, 32) via a common valve unit (38) are controllable. Air suspension system according to one of Claims 1 to 9 , characterized in that the lifting and lowering device (72) is assigned at least one pilot valve (80) and a holding valve (98). Air suspension system according to one of Claims 1 to 10 , characterized in that when the first valve (34), the second valve (82) is closed by pressurization via a control line (104), wherein a bypass (106) is provided, via which the second valve (82) associated air spring ( 22) is vented. Air suspension system according to one of Claims 1 to 11 , characterized in that at least two spring arrangements (64, 23) are provided which are associated with a respective axis (30, 28) of the vehicle and which each have an air spring (24, 22), wherein the first air spring (24) of the first A height sensor means (62) for determining a spring height of the air spring (24) or the corresponding first axis (30) is associated, wherein the height sensor means (62) of the first air spring (24) of the first axis (30) additionally a sensor device with a pressure sensor (60) which communicates with a sensor device with a pressure sensor (52), the second air spring (22) of the second axis (28).

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